Vue.js 2.x Development Build With Hot Reloadi…

vue init webpack <PROJECT_NAME>

...
  "scripts": {
    "dev": "node build/dev-server.js",
    "start": "node build/dev-server.js",
    "build": "node build/build.js",
    "unit": "cross-env BABEL_ENV=test karma start test/unit/karma.conf.js --single-run",
    "e2e": "node test/e2e/runner.js",
    "test": "npm run unit && npm run e2e",
    "lint": "eslint --ext .js,.vue src test/unit/specs test/e2e/specs"
  },
...

```text
...
  "scripts": {
  	...
  	"watch": "node build/watch-build-dev.js"
  },
...

require('./check-versions')()

// EDIT: process.env.NODE_ENV = 'production'
process.env.NODE_ENV = 'development'

var ora = require('ora')
var rm = require('rimraf')
var path = require('path')
var chalk = require('chalk')
var webpack = require('webpack')
var config = require('../config')
// EDIT: var webpackConfig = require('./webpack.prod.conf')
var webpackConfig = require('./webpack.watch.conf')

// EDIT: ora('building for production...')
var spinner = ora('building for development...')
spinner.start()

rm(path.join(config.build.assetsRoot, config.build.assetsSubDirectory), err => {
  if (err) throw err
  webpack(webpackConfig, function (err, stats) {
    spinner.stop()
    if (err) throw err
    process.stdout.write(stats.toString({
      colors: true,
      modules: false,
      children: false,
      chunks: false,
      chunkModules: false
    }) + '\n\n')

    // EDIT: remove the following to avoid watch quit upon error
    /*
    if (stats.hasErrors()) {
      console.log(chalk.red('  Build failed with errors.\n'))
      process.exit(1)
    }
     */

    console.log(chalk.cyan('  Build complete.\n'))
    // EDIT: remove
    /*
    console.log(chalk.yellow(
      '  Tip: built files are meant to be served over an HTTP server.\n' +
      '  Opening index.html over file:// won\'t work.\n'
    ))
     */
  })
})

'use strict'
const path = require('path')
const utils = require('./utils')
const webpack = require('webpack')
const config = require('../config')
const merge = require('webpack-merge')
const baseWebpackConfig = require('./webpack.base.conf')
const CopyWebpackPlugin = require('copy-webpack-plugin')
const HtmlWebpackPlugin = require('html-webpack-plugin')
const ExtractTextPlugin = require('extract-text-webpack-plugin')
const OptimizeCSSPlugin = require('optimize-css-assets-webpack-plugin')

// EDIT: change to development
// const env = require('../config/prod.env')
const env = require('../config/dev.env')

const webpackConfig = merge(baseWebpackConfig, {
  module: {
    rules: utils.styleLoaders({
      sourceMap: config.build.productionSourceMap,
      extract: true,
      usePostCSS: true
    })
  },
  devtool: config.build.productionSourceMap ? config.build.devtool : false,
  output: {
    path: config.build.assetsRoot,
    // EDIT: remove hash
    // filename: utils.assetsPath('js/[name].[chunkhash].js'),
    // chunkFilename: utils.assetsPath('js/[id].[chunkhash].js')
    filename: utils.assetsPath('js/[name].js'),
    chunkFilename: utils.assetsPath('js/[id].js')
  },
  plugins: [
    // http://vuejs.github.io/vue-loader/en/workflow/production.html
    new webpack.DefinePlugin({
      'process.env': env
    }),
    // UglifyJs do not support ES6+, you can also use babel-minify for better treeshaking: https://github.com/babel/minify
    // EDIT: disable js minify
    /*
    new webpack.optimize.UglifyJsPlugin({
      compress: {
        warnings: false
      },
      sourceMap: config.build.productionSourceMap,
      parallel: true
    }),
     */
    // extract css into its own file
    new ExtractTextPlugin({
      // EDIT: remove hash
      // filename: utils.assetsPath('css/[name].[contenthash].css'),
      filename: utils.assetsPath('css/[name].css'),
      // set the following option to `true` if you want to extract CSS from
      // codesplit chunks into this main css file as well.
      // This will result in *all* of your app's CSS being loaded upfront.
      // EDIT: if not then splitting vendor.css will cause javascript error
      // allChunks: false,
      allChunks: true,
    }),
    // Compress extracted CSS. We are using this plugin so that possible
    // duplicated CSS from different components can be deduped.
    // EDIT: disable CSS minify
    /*
    new OptimizeCSSPlugin({
      cssProcessorOptions: config.build.productionSourceMap
      ? { safe: true, map: { inline: false } }
      : { safe: true }
    }),
     */
    // generate dist index.html with correct asset hash for caching.
    // you can customize output by editing /index.html
    // see https://github.com/ampedandwired/html-webpack-plugin
    new HtmlWebpackPlugin({
      filename: config.build.index,
      template: 'index.html',
      inject: true,
      // EDIT: disable minify
      /*
      minify: {
        removeComments: true,
        collapseWhitespace: true,
        removeAttributeQuotes: true
        // more options:
        // https://github.com/kangax/html-minifier#options-quick-reference
      },
       */
      minify: false,
      // necessary to consistently work with multiple chunks via CommonsChunkPlugin
      chunksSortMode: 'dependency'
    }),
    // keep module.id stable when vender modules does not change
    new webpack.HashedModuleIdsPlugin(),
    // enable scope hoisting
    // EDIT:
    // new webpack.optimize.ModuleConcatenationPlugin(),
    // split vendor js into its own file
    new webpack.optimize.CommonsChunkPlugin({
      name: 'vendor',
      minChunks: function (module) {
        // any required modules inside node_modules are extracted to vendor
        // EDIT
        return (
          module.resource &&
          /\.(js|css|sass|scss|less)$/.test(module.resource) &&
          module.resource.indexOf(
            path.join(__dirname, '../node_modules')
          ) === 0
        )
      }
    }),
    // extract webpack runtime and module manifest to its own file in order to
    // prevent vendor hash from being updated whenever app bundle is updated
    new webpack.optimize.CommonsChunkPlugin({
      name: 'manifest',
      minChunks: Infinity
    }),
    // This instance extracts shared chunks from code splitted chunks and bundles them
    // in a separate chunk, similar to the vendor chunk
    // see: https://webpack.js.org/plugins/commons-chunk-plugin/#extra-async-commons-chunk
    new webpack.optimize.CommonsChunkPlugin({
      name: 'app',
      async: 'vendor-async',
      children: true,
      minChunks: 3
    }),

    // copy custom static assets
    new CopyWebpackPlugin([
      {
        from: path.resolve(__dirname, '../static'),
        to: config.build.assetsSubDirectory,
        ignore: ['.*']
      }
    ])
  ],
  // EDIT: enable watch
  watch: true,
  // EDIT: enable watch for modules
  // https://github.com/vuejs-templates/webpack/issues/378
  watchOptions: {
    aggregateTimeout: 300,
    poll: 1000
  }
})

if (config.build.productionGzip) {
  const CompressionWebpackPlugin = require('compression-webpack-plugin')

  webpackConfig.plugins.push(
    new CompressionWebpackPlugin({
      asset: '[path].gz[query]',
      algorithm: 'gzip',
      test: new RegExp(
        '\\.(' +
        config.build.productionGzipExtensions.join('|') +
        ')$'
      ),
      threshold: 10240,
      minRatio: 0.8
    })
  )
}

if (config.build.bundleAnalyzerReport) {
  const BundleAnalyzerPlugin = require('webpack-bundle-analyzer').BundleAnalyzerPlugin
  webpackConfig.plugins.push(new BundleAnalyzerPlugin())
}

module.exports = webpackConfig

npm run watch
# output
> hello@1.0.0 watch /code/vue/hello
> node build/watch-build-dev.js

? building for development...

 DONE  Compiled successfully in 2923ms                                5:32:25 PM

Hash: fcfe8096ae777ea47bf7
Version: webpack 2.7.0
Time: 2923ms
             Asset       Size  Chunks                    Chunk Names
            app.js     780 kB       0  [emitted]  [big]  app
static/css/app.css   93 bytes       0  [emitted]         app
        index.html  845 bytes          [emitted]         

  Build complete.